Notes are frequently taken using classic pen and paper systems. Students, for example, generally purchase new notebooks every new school year for various subject matters, and/or when a notebook is filled up. Pages of notebooks may go unused, and thus, trees and other natural resources are wasted. Attempts have been made to migrate to other note taking formats, such as digital tablet devices and reusable writing surfaces. Many users prefer the feel of writing with a writing instrument on paper, and thus, do not adjust well to the feel of taking notes with digital devices. Furthermore, many classroom environments do not allow the use of electronic devices. Additionally, reusable writing surfaces, such as whiteboards, may wipe off easily, causing difficulty with note storage and portability.
Thermochromic ink pens can be used to write on paper and can be effectively erased. Thermochromic ink typically changes from opaque (i.e., color) to transparent when heat is applied (e.g., due to friction from an eraser being rubbed on the ink, or when the paper with thermochromic ink is placed in an oven or microwave oven). One example of a thermochromic ink pen is the FRIXION™ thermochromic ink pen manufactured by Pilot Corporation. A description of the FRIXION™ thermochromic ink pen can be found in Miki, Masuda, The Science Behind Frixion Erasable Pens, http://www.nippon.com/en/features/c00520/ dated Aug. 24, 2016. Some exemplary thermochromic inks are described in U.S. Pat. No. 4,028,118, U.S. Pat. No. 4,720,301, U.S. Pat. No. 4,720,301, and U.S. Pat. No. 8,616,797.
Synthetic paper generally contains no wood pulp or natural fibers (as found in standard paper), and is commonly formed from polypropylene resin along with inorganic fibers, although many different types of synthetic papers were known (e.g., including different types of synthetic papers referred to as stone paper). Synthetic paper frequently has a base layer covered with a surface layer. Among other things, the base layer of synthetic paper may be formed, for example, polyethylene, polypropylene, high-density polyethylene, polyester, and other plastics. The surface layer adds a bright surface finish, high opacity and smooth texture. Synthetic-paper is also more durable that traditional paper. Many synthetic papers are tear-resistant, wear-resistant, chemical-resistant, heat-resistant, and/or grease-resistant relative to traditional paper. This makes synthetic paper a good option for use in environments where the notebook could be damaged. For example, when used with many traditional pens and markers, notes and/or publications written on synthetic paper may be read in the bath, pool, spa, shower, or while boating, fishing, skiing, snowmobiling or scuba diving.